SA Graan February 2019

Biological control of Sclerotinia diseases

can be achieved through two pathways, i.e.

directly through the use of actively growing

micro-organisms to target and parasitise

the pathogen, or indirectly through sec-

ondary metabolites produced to supress

pathogen growth, promote plant health and

induce resistance mechanisms.

The former focuses on the use of the fun-

gus

Coniothyrium minitans

, which reduces

sclerotial survival through degrading the

sclerotia in fields previously infested with

S. sclerotiorum

. The latter includes fungal

and bacterial organisms such as

Trichoder-

spp. and

Bacillus

spp. There are multi-

ple biological control products available in

South Africa. However, the efficacy of many

of these within our South African context

needs to be confirmed.

Fungicides

There are limited registered fungicides

in South Africa. Currently, benomyl and

procymidone are used on peas and sun-

flower. Furthermore, the exorbitant cost of

the chemicals and their application as well

as the potential requirement for multiple

sprays are economic risks for producers.

Forecasting the risk of Sclerotinia diseases,

based on agronomic and weather variables,

could benefit producers by identifying inter-

vention thresholds and optimising the tim-

ing of management strategies.

These risk assessments have been success-

ful internationally for canola and soybean.

The systems range from simple check lists

to more advanced mathematical modelling,

which is ultimately visualised as a risk per-

centage or proportion, followed by a recom-

mendation to apply (as well as application

timing) or withhold fungicide applications.

The change in agronomic decisions, envi-

ronmental and weather conditions, man-

agement practices and the susceptibility of

germplasm has led to an increase in the im-

portance of Sclerotinia diseases worldwide.

The greater the prevalence and severity

of the disease, the lower the yield and the

greater the inoculum build up.

In the 2017/2018 season, sunflower and

soybean epidemics causing up to 80%

yield losses were reported in the Eastern

Free State. During 2014, in South Africa,

the effects of Sclerotinia stem rot of canola

gained more attention due to the greater

prevalence of the disease during the season

compared to previous years.

Problematic in economi-

cally important crops

Although extensive literature is available

with regards to Sclerotinia diseases, this

disease remains problematic in economi-

cally important crops, and the pathogen’s

behaviour locally needs to be clarified.

This investigation is a priority of the South

African National Sclerotinia Research Net-

work. The spread of

S. sclerotiorum

into

critical South African crop production areas

and its associated yield losses, highlight

the importance of identifying and deploying

effective management measures to safe-

guard agricultural land against the initial in-

cursion of this pathogen.

For more information please contact Lisa

Rothmann at

coetzeeLA@ufs.ac.za

and fol-

low the South African Sclerotinia Research

Network on Facebook, Instagram and Twit-

ter.

February 2019

Nuwe lojaliteitseisoen

sit beloning vir klante voort

ie tweede seisoen van NWK se Loja-

liteitsprogram – wat op 1 Mei verlede

jaar afgeskop het – is flink op dreef. Alle

klante of entiteite wat teen einde April

geregistreer het, staan die kans om later

vanjaar ’n splinternuwe sleepwaentjie in te

palm, terwyl nuwe toetreders boonop vir

koopbewyse in aanmerking kom.

Registreer en wen

Klante wat tot en met 30 April registreer, het

’n kans om een van twee R3 000-koopbewy-

se van NWK Retail te wen. Die trekkings vind

plaas op:

28 Februarie vir registrasies wat tussen

1 Desember 2018 en 27 Februarie 2019

gedoen is; en

30 April vir registrasies tussen 28 Feb-

ruarie en 29 April vanjaar.

Buiten vir die koopbewyse kom almal

wat sedert die implementering van die

Lojaliteitsprogram op 1 September 2017

geregistreer het, in aanmerking vir ’n

groot prys. Op 31 Mei vanjaar sal een ge-

registreerde NWK-klant die gelukkige wen-

ner van ’n Jurgens-sleepwaentjie ter waarde

van R14 000 word.

Sedert die Lojaliteitsprogram in September

2017 geloods is, het NWK-klante wat voor

30 April 2018 geregistreer het, ’n totaal

van 2,8 miljoen punte verdien. Dit ver-

teenwoordig ’n waarde van R8 miljoen

en is hoofsaaklik deur die benutting van

silodienste en deur insetmiddele by NWK

aan te koop, verdien. Dié lojale klante is

beloon met krediet vir verdere aankope

of met aandele in NWK Beperk of NWK

Beherend Beperk.

Waarom registreer?

Faktore wat NWK se program uniek maak,

is die feit dat nie net sekere groeperings

daarby kan baat nie. Boonop word klante

jaarliks beloon en hoef hulle nie etlike jare

te wag om die volle voordeel te ontvang nie.

Gaan só te werk om ook deel te word van

die program en word deel van meer as 1 000

klante of entiteite wat reeds maai wat hulle

gesaai het:

Sluit aanlyn by

www.nwk.co.za

op die

NWK Online-bladsy aan.

Kontak NWK deur middel van die

webtuiste

www.nwklojaliteit.co.za

Doen navraag by enige NWK Retail-

winkel, graansilo of NWK Finansiering

by Hoofkantoor.

Ná registrasie word klante deel van

die program en kwalifiseer hulle vir lo-

jaliteitspunte. Hoe meer besigheid met

NWK gedoen word, hoe groter is die

voordeel wat verdien word. Lees meer

oor dié program waardeur NWK in sy

klantebasis terugploeg op die webtuiste

www.nwklojaliteit.co.za

JACQUES DE WET,

bemarkingsbestuurder, NWK

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